Fanlight
A fanlight is a window above a door. The name comes from the earliest examples, which were semicircular windows with glazing bars radiating like the ribs of a fan. They became a feature of Georgian doorways in the eighteenth century, when the bars were curved into sunbursts, webs and delicate patterns, and let light into the hall behind a solid front door.
In modern use the word covers any glass panel above a door, whatever its shape. Rectangular lights of this kind are also called transoms, and in North America the half-round window is sometimes called a transom window or a sunburst window.
Leaded, stained, etched and bevelled glass are all used in fanlights, and a fanlight is often the most visible piece of decorative glass on a house.